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Tuesday, June 19, 2012

The Brain: A Highly Redundant System

When I helped create telephone switches and datacomm equipment (back when I was young enough not to be considered senile and useless by private industry because I am over 40), many components were redundant: there would be both an A and a B side to the switch. If a power supply failed on the A side, then the B side power supply took over. If the A side incoming fiber card failed, the B side took over. The theory was that if one card failed, it would inform the operator, and the other side would take over. The chances of one of these components both failing before the phone company had a chance to swap out the bad card was quite small.

This is what redundancy gives you: if your equipment is 98% reliable, and you can silently (or nearly silently) switch over to another piece of equipment of similar reliability, and you can get the first failed equipment replaced within a couple of hours, the likelihood of losing service was tiny--fractions of 1%. (Some equipment, such as individual cards responsible for providing service to several subscribers, were usually not redundant. This was a cost tradeoff.)

If you have seen the X-ray of the guy with a spear through his head -- and who managed to remain conscious and talking through the ordeal -- think of this as a reminder that an astonishing amount of your brain is clearly redundant. (Or perhaps, not even used!)

5 comments:

For example, you can probably remember what was the first car you owned. It is not something you think about daily but if I asked you then you could probably tell me. Will he no longer be able to remember such things? Can these memories be destroyed while leaving current cognitive functions untouched?

There's a common idea floating around that "we only use 10% of our brains", which is often used in comic books to justify telepathy or other superpowers ("he can use the other 90% that most people don't use"). Thing is, it's a misperception. It's based on studies that showed that most people are only using 10% of their brains at any given moment. Because nobody reads, does math, sings, plays the piano, rides a bike, runs, swims, feels love, feels hate, smells cinnamon, smells a skunk, climbs a tree, and ties their shoelaces all at once. Different parts of the brain are active at different times, but over time the whole 100% of the brain is used. So the guy who got a spear through his head may have been conscious and talking, but some brain function of his was impaired. Maybe he wouldn't have been able to do math, or maybe he wouldn't have recognized the smell of roses, or maybe music would have sounded like noise to him -- it's impossible to know. But some function of his brain would have been damaged.

However, the brain is plastic, that is, malleable. (The material we call "plastic" has that name because it's easily formed into different shapes.) So whatever function of his brain he lost, it's possible (not 100% guaranteed, but possible) that he'll be able to retrain his brain so that the still-working parts can pick up the function(s) performed by the damaged parts.

... Ah. Just read the article: "... he is worried about the fact that he can't use his left side properly." Which makes sense given that the spear went through the right side of his brain. So that's the function he lost and will have to retrain.

rmunn pretty much said what I was about to say, but I'd add that I'm fairly confident that even though we use 100% of our brains, there's likely a bit of redundancy in there. It would make sense, so that we could more easily recover from injury. (By no means would I expect it to be a failsafe system, by any means, though.)

The comic book idea that we use only 10% of our brain, and the remaining 90% was useful for telepathy and other special powers, never made sense from me, either from an Evolutionary or a Creationist point of view.

Why would each and every person have special powers and gifts, that would give both individuals and groups advantages over other individuals and groups, but only a handful of people over all time figure out how to use them?